A.2~4mm B.3~5mm C.5~8mm D.8~10mm E.以上都不是
A.遺傳性和后天性擁擠 B.單純擁擠和復(fù)雜擁擠 C.替牙列擁擠和恒牙列擁擠 D.前牙擁擠和后牙擁擠 E.青少年擁擠和成人擁擠
A.91%~98% B.85%~90% C.80%~93% D.60%~70% E.20%~50%